<!DOCTYPE html><html><head><title>Login</title><style>body{display:flex;height:100vh;justify-content:center;align-items:center;background:#f5f5f5}.login-box{background:white;padding:20px;border-radius:5px;box-shadow:0 0 10px rgba(0,0,0,0.1)}input{margin:5px 0;padding:8px;width:100%}button{width:100%;padding:8px;background:#007bff;color:white;border:none;border-radius:3px}</style></head><body><div class="login-box"><h2>Login</h2><input type="text" placeholder="Username" id="username"><input type="password" placeholder="Password" id="password"><button onclick="login()">Login</button></div><script>function login(){alert('Logged in as '+document.getElementById('username').value)}</script></body></html>